Oral misoprostol for induction of labour

RHL Summary

11 August 2014
Image of woman in labour stretching her back while seated on the edge of the bed.
Lieve Blancquaert

Findings of the review: Seventy-one trials of mixed quality were included in the meta-analysis in this review. Based on thirty-seven trials (6417 women) that had compared oral and vaginal misoprostol no statistically significant difference was found in primary outcomes of serious neonatal morbidity/death or serious maternal morbidity or death. Fewer babies were born with a low Apgar and fewer women had postpartum haemorrhage in the oral misoprostol group in comparison with the vaginal misoprostol group. However, oral misoprostol group had more cases with meconeum-stained liquor. The results were highly heterogeneous for vaginal birth not achieved within 24 hours, uterine hyperstimulation with fetal heart rate changes, and caesarean section rates. Meta-analysis of nine trials (1282) women that had compared oral misoprostol with intravenous oxytocin found lower caesarean section rate in the oral misoprostol group, but increased rate of the meconeum-stained liquor. Twelve trials (3859 women) that had compared oral misoprostol and vaginal dinoprostone found that fewer women underwent caesarean section in the oral misoprostol group. In subgroup analysis of women with ruptured membranes, more women achieved vaginal birth within 24 hours in the oral misoprostol group. According to meta-analysis of nine trials (1109 women) that had compared oral misoprostol with placebo, more women had vaginal birth within 24 hours, women needed less oxytocin, and had a lower caesarean section rate in the oral misoprostol group. In the subgroup of women with ruptured membranes, more women achieved vaginal birth within 24 hours in the oral misoprostol group. Five trials (681 women) that had compared oral misoprostol with intracervical prostaglandin, reported a higher rate of uterine hyperstimulation with fetal heart rate changes in the oral misoprostol group, but more women achieved vaginal birth in 24 hours in this group. No difference was found in subgroup analysis of different oral doses and regimens of misoprstol. Oral misoprostol was used in 160 women with previous caesarean section with no cases of uterine rupture.

Implementation: As a labour induction agent, oral misoprstol is effective in achieving vaginal birth. It is more effective than placebo and results in fewer caesarean sections than vaginal dinoprost. Oral misoprostol use in women with ruptured membranes results in fewer caesarean sections in comparison with oxytocin use for induction of labour. These findings support the 2011 WHO recommendation to use oral misoprostol 25 µg two hourly for induction of.


Cochrane review

Citation: Alfirevic Z, Aflaifel N, Weeks A. Oral misoprostol for induction of labour. Cochrane Database of Systematic Review 2014, 6. Art. No.: CD001338. DOI: 10.1002/14651858.CD0013 38.pub3.

Abstract

Background

Misoprostol is an orally active prostaglandin. In most countries misoprostol is not licensed for labour induction, but its use is common because it is cheap and heat stable.

Objectives

To assess the use of oral misoprostol for labour induction in women with a viable fetus.

Search methods

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (17 January 2014).

Selection criteria

Randomised trials comparing oral misoprostol versus placebo or other methods, given to women with a viable fetus for labour induction.

Data collection and analysis

Two review authors independently assessed trial data, using centrally-designed data sheets.

Main results

Overall there were 76 trials (14,412) women) which were of mixed quality.

In nine trials comparing oral misoprostol with placebo (1109 women), women using oral misoprostol were more likely to give birth vaginally within 24 hours (risk ratio (RR) 0.16, 95% confidence interval (CI) 0.05 to 0.49; one trial; 96 women), need less oxytocin (RR 0.42, 95% CI 0.37 to 0.49; seven trials; 933 women) and have a lower caesarean section rate (RR 0.72, 95% CI 0.54 to 0.95; eight trials; 1029 women).

In 12 trials comparing oral misoprostol with vaginal dinoprostone (3859 women), women given oral misoprostol were less likely to need a caesarean section (RR 0.88, 95% CI 0.78 to 0.99; 11 trials; 3592 women). There was some evidence that they had slower inductions, but there were no other statistically significant differences.

Nine trials (1282 women) compared oral misoprostol with intravenous oxytocin. The caesarean section rate was significantly lower in women who received oral misoprostol (RR 0.77, 95% CI 0.60 to 0.98; nine trials; 1282 women), but they had increased rates of meconium-stained liquor (RR 1.65, 95% CI 1.04 to 2.60; seven trials; 1172 women).

Thirty-seven trials (6417 women) compared oral and vaginal misoprostol and found no statistically significant difference in the primary outcomes of serious neonatal morbidity/death or serious maternal morbidity or death. The results for vaginal birth not achieved in 24 hours, uterine hyperstimulation with fetal heart rate (FHR) changes, and caesarean section were highly heterogenous - for uterine hyperstimulation with FHR changes this was related to dosage with lower rates in those with lower doses of oral misoprostol. However, there were fewer babies born with a low Apgar score in the oral group (RR 0.60, 95% CI 0.44 to 0.82; 19 trials; 4009 babies) and a decrease in postpartum haemorrhage (RR 0.57, 95% CI 0.34 to 0.95; 10 trials; 1478 women). However, the oral misoprostol group had an increase in meconium-stained liquor (RR 1.22, 95% CI 1.03 to 1.44; 24 trials; 3634 women).

Authors' conclusions

Oral misoprostol as an induction agent is effective at achieving vaginal birth. It is more effective than placebo, as effective as vaginal misoprostol and results in fewer caesarean sections than vaginal dinoprostone or oxytocin.

Where misoprostol remains unlicensed for the induction of labour, many practitioners will prefer to use a licensed product like dinoprostone. If using oral misoprostol, the evidence suggests that the dose should be 20 to 25 mcg in solution. Given that safety is the primary concern, the evidence supports the use of oral regimens over vaginal regimens. This is especially important in situations where the risk of ascending infection is high and the lack of staff means that women cannot be intensely monitored.

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